Driving safety is crucial for drivers and passengers. Many techniques are available for assisting driving safety. For example, when reversing a vehicle, images behind the vehicle can be captured by a rear camera. Thus, in addition to observing with the naked eye, a driver may also determine whether obstacles or pedestrians are behind the vehicle though images captured by a rear safety assist system.
Safety assist systems (e.g., all-around-view driver assistance systems, forward collision avoidance systems, rear safety assist systems, and side blind-spot detection systems) are usually equipped with a vehicle camera for capturing images outside a vehicle. Before being shipped out of the factory, the vehicle cameras installed in vehicles need to be calibrated first.
In a conventional human-interface calibration, a vehicle camera is manually fine-tuned by a calibration staff, such that characteristic patterns in captured images satisfy predetermined conditions and then image capture is adjusted to correct position/direction of the camera through the human-interface operation. A system then calculates camera extrinsic parameters and camera intrinsic parameters for coordinate conversion.
However, due to human factors such as different observations and different carefulness of different calibration staff, image errors are resulted in the current calibration procedure. Further, the calibration procedure requires paying special attention on setting of calibration reference patterns and solving extrinsic parameters may be a tremendous computation load on the system.